Remedial system: a pollution control device for utilizing and abating volatile organic compounds

ABSTRACT

A remedial pollution control system for treating volatile organic compounds that may include a vapor concentrator connected to a line that is laden with volatile organic compounds, the concentrator has an organic condensate output line and a vapor output line; a mixing chamber adapted to receive air provided from an air supply line, combustible fuel from an alternate fuel supply line, and a vapor stream from the vapor output line to produce a mixed fuel supplied to an internal combustion engine, a control mixing system with a controller for producing a proper air to fuel ratio in the mixed fuel supply, and power generated to operate other devices used to more efficiently abate volatile organic compounds and reduce greenhouse gas emissions.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a divisional of application Ser. No. 12/468,789,filed May 19, 2009, which claims the benefit and the priority of U.S.Provisional Patent Application No. 61/054,452, filed May 19, 2008, theentire contents of which is incorporated herein by reference.

BACKGROUND

Vapor streams containing volatile and semi-volatile organic compounds(VOCs and SVOCs) are produced by industrial processes; as a result ofthe transfer of liquids from one containment body to another due to thedisplacement of air or liquid, by their volatilization during theindustrial process or by contaminated soil remediation or otherenvironmental cleanup operations. These processes typically use eithervacuum or pressure pumps, blowers or compressors. Air displaced in theprocess becomes saturated with vapors containing VOCs and SVOCs that cancause environmental damage or health issues.

Until most recently, control and destruction of these vapors wastraditionally done with different pollution control devices thatcontrolled and/or oxidized the vapors. Suitable devices have includedopen burning flares, thermal oxidizers, catalytic oxidizers andconventional internal combustion engines (ICE). A conventional ICE isone that utilizes a standard carburetor which has one fuel input and oneair input. Recently implemented environmental regulations or changes toexisting regulations have made the present form of oxidizers either toopolluting, unsafe to operate, too expensive or obsolete. Alternatively,VOCs and SVOCs can be removed and controlled by adsorption ontoactivated carbon, but excessive cost and handling are of concern due tothe large volumes of carbon typically required for proper abatement.

Industrial process vapor streams vary in volume/density and BTU contentof VOCs and SVOCs which directly impacts the composition of the air fuelmixture going to an oxidation vehicle. While carbon adsorption is notadversely affected by a change in air fuel mixture, safety and controllimitations for current oxidation technologies such as flares,thermal/catalytic oxidizers and conventional ICE's can requiresignificant and expensive amounts of alternate fuel source in order tocombust the VOCs and SVOCs in the vapor stream. In addition, traditionaloxidizers are usually physically large in size and are oversized inorder to handle fluctuation of the BTU content of the vapor stream. As aresult, traditional oxidizers burn excessive amounts of alternate fuel,and therefore generate significant amount of greenhouse gas emissionswithout effectively recovering the energy available from the VOCs andSVOCs in the vapor stream.

Similarly, the adsorption of organic compounds onto an activated carbonprocess bed requires a large footprint storage container. A large volumeof charcoal is required in order to process VOCs in a comparable amountof time as that of other oxidizing vehicles. Additionally, once theactivated carbon has reached its maximum “spent” loading capacity it hasto be replaced by a new container of charcoal. The spent charcoal has tobe desorbed to reprocess/recover it for reuse. This reprocessingrequires energy (alternate fuel source), generates additional wastestreams and produces greenhouse gas emissions. Furthermore, carbon isunsafe for processing high VOC content vapor streams because the carbonmay easily ignite.

A conventional ICE attempts to use the volatile vapor stream as theprimary fuel source. However, it does not have the capability to handlethe rapidly changing air flow volume/density and varying BTUconcentrations found in the process vapor stream. As it uses largeamounts of an alternate fuel source (typically propane) mixed with theprocess vapor stream in order to operate correctly, a conventional ICEis inefficient in reduction of the vapor stream of VOCs/SVOCs andgenerates more secondary pollutants such as NOx and CO when compared tothe present invention, which utilizes a unique control/mixing systemwith multiple fuel/air valves, specialized software and a custom airfuel ratio controller.

SUMMARY OF THE INVENTION

An aspect of an embodiment of the present invention is directed toward aremedial pollution system for concentrating and capturing energy foundin the process vapor stream of various industrial processes, oil and gasproduction fields and any vessel storing hydrocarbons; and for safelyusing, treating and/or disposing of VOCs and/or SVOCs. Examples ofvessels storing hydrocarbons include above ground and undergroundstorage and process tanks, fixed roof and floating roof storage/processtanks, vacuum tanks, pressure tanks, ship and barge storage/processtanks and any vessel that can contain hydrocarbons for storage and/orprocess purposes. As used hereinafter, the terms “volatile organiccompounds,” “organic volatiles,” “vapor stream,” “head gas,” “gas wastestream,” and “process gas” will be used interchangeably and are intendedto cover both VOCs and SVOCs. Similarly, the term “chiller” is usedinterchangeably with “condenser,” “ICE” is used interchangeably with“internal combustion engine” and “combustor,” “remedial system” is usedinterchangeably with “pollution control device” and the term “VOCs” isalso meant to include SVOCs. A “direct chiller” is one where refrigerantis circulated directly in the heat exchanger in contact with the processstream. An “indirect chiller” is one where the refrigeration unit chillscoolant that is pumped to the heat exchanger that is in contact with theprocess stream.

In one exemplary embodiment, the pollution control device includes aconcentrator for abating and/or reducing the amount of energy containedin the process gas, and an ICE for generating energy from the remainingprocess gas. Exemplary embodiments of different concentrators include,but are not limited to, condensers, cryogenic devices, scrubbers, carbonor other suitable adsorption/absorption materials and membraneseparation devices. In various embodiments, the remedial system furtherincludes an automated control/mixing system with air fuel ratiocontroller. In other embodiments, the remedial system also includes anelectricity generator and/or hydraulic pump and/or other type ofmechanical device to harvest and convert the energy produced from theICE to other forms that can power the equipment of the remedial system.In yet another embodiment of the present invention, the generated poweris used to operate a compressor and oxygen-nitrogen separator to inertthe process for safety considerations and to inject stripped oxygendownstream in the process. This balanced approach of stripping andreinjecting oxygen not only results in a safer work environment, itrequires less alternate fuel energy source as the correct air fuel ratiofor combustion is established without the need for large amounts ofadditional fuel or air.

In one exemplary embodiment, the concentrator is a condenser. In theexemplary embodiment, the remedial system includes an input lineconnected to the condenser and adapted to receive VOCs from a source orprocess, a control/mixing system adapted to receive a vapor stream fromthe condenser, and an ICE. In a further exemplary embodiment, thecondenser has a liquid output line and a vapor output line, thecontrol/mixing system is adapted to receive and control air flow from asupply line, flow from an alternate fuel supply line, and to receive andcontrol the vapor output line from the condenser/chiller, wherein thecontrol/mixing system has a mixed fuel outlet line that is connected toan ICE.

In one exemplary embodiment, there is provided a radiator system adaptedto heat the process air inside the chiller to increase vaporcondensation and also to be used as a defrost cycle for variousapplications. In another embodiment, there is provided a holding tankconnected to the condenser liquid output line for receiving and storingthe volatile organic condensate for later reclamation.

In a further exemplary embodiment, the remedial system may include avacuum pump having a pump output line. The vacuum pump is connected tothe vapor output line of the VOC source or industrial process. There isprovided a recycle line that connects the pump output line to thecondenser input line. A compressor may also be provided. The compressorincludes an input line, connected to a VOC source or industrial process,and a VOC output line which is used to power an oxygen-nitrogenseparator and/or to pressurize and recapture VOCs from the process forreclamation.

In another exemplary embodiment, the remedial system includes acatalytic converter connected to the internal combustion engine. In yetanother exemplary embodiment there is provided an engine driven pump, agenerator and/or a hydraulic pump to convert energy produced by theinternal combustion engine into mechanical power, electricity and/orhydraulic power.

In one embodiment, the remedial system is hooked up to a waste processgas stream that would otherwise be vented to a flare. This embodimentmay not require a condenser/chiller but still may utilize a generatorand/or hydraulic power to operate a compressor or the remedial systemwill direct drive a compressor, in order to compress and re-inject thewaste gas stream back into a process line for reuse.

Another aspect of an embodiment of the present invention is directedtoward a remedial method for utilizing VOCs that includes collecting aprocess stream laden with VOCs, chilling and condensing the VOCs in aplurality of stages to produce a liquid condensate, which is routed to aholding tank and a vapor feed stream, which is routed to an ICE. An airsupply stream and an alternate fuel stream are provided and mixed withthe vapor feed stream to produce a mixed fuel stream. The mixed fuelstream is maintained at or near a stoichiometric air fuel ratio using aspecially designed control/mixing system which blends fuels from two ormore varying sources, with atmospheric air from multiple sources basedon various control feed back loops. The mixed fuel stream is then drawninto the engine intake manifold using an engine manifold vacuum that mayhave a turbo charger, to create a near ideal stoichiometric combustiblegas stream. The combustible gas stream is consumed by an ICE to generatemechanical power. The mechanical power is then converted to other formsof energy. For example, a generator can be used to generate electricenergy or a hydraulic pump can be used to generate hydraulic energy.Alternatively, other mechanical devices can also be used to produce anddirect energy to the chiller and/or to other types of concentrator.

In one exemplary embodiment, where the input process gas stream is onethat would otherwise go to a flare for oxidation, the process gas streamladen with VOCs is compressed and fed back to a process line for storageor industrial use. In another exemplary embodiment, a portion or all ofthe process gas stream is recycled back to the condenser.

In a further exemplary embodiment, the remedial system includesproviding nitrogen gas to a process gas stream that is laden with VOCsand/or to a designated volatile source such as a wastewater treatmenttank, for example. In this way, the oxygen content in the process gasstream or tank is suppressed by displacement of the oxygen with nitrogenfor safety reasons and/or to meet a lower explosion limit (LEL)requirement. In one embodiment, the nitrogen gas is obtained from anoxygen-nitrogen gas separator powered by the ICE. In furtherembodiments, oxygen and remaining atmospheric air obtained from theoxygen-nitrogen gas separator are fed back into the process gas streamthat is downstream of the designated volatile source. Oxygen is addedback into the process gas stream to enable oxidization. In this way,only minimal alternate fuel and/or oxygen are needed at thecontrol/mixing system to provide a combustible fuel supply to the ICE.

In another exemplary embodiment, the pollution control device is hookedup to a fume line that captures displaced gasoline vapors from vehiclesand/or underground storage tanks when the vehicles or undergroundstorage tanks are being refueled. The fume line from the gasolinedispenser is routed back to an underground storage gas tank, which isconnected to the remedial system of the present invention. Fumes canthus be abated on site, or processed to produce a VOC condensate thatcan be reused as a fuel source to run the remedial system or otherequipment on site, or to produce energy that can be put back into theenergy grid.

Other aspects and features of the remedial device provided herein may bebetter appreciated as the same become better understood with referenceto the specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying diagrams, together with the specification, illustrateexemplary embodiments of the present invention and together with thedescription, serve to explain the principles of the present invention.In the following drawings, only certain pollution sources are shown byway of illustration. As those skilled in the art will recognize, thepollution sources may be embodied in many different forms and should notbe construed as being limited to the drawings set forth herein.

FIG. 1 is a block diagram of a pollution control device for treatingvolatile organic compounds according to embodiments of the presentinvention. An air pollution source is routed to a concentrator and/orproportionally bypassed to the control mixing system of the combustor.

FIG. 2A is a process diagram of a remedial system for treating and/orcapturing volatile organic compounds from an oil and/or natural gas wellor production field using a concentrator that utilizes a direct chiller.VOCs are introduced to the control/mixing system to be processed forcombustion. Vapors are destroyed in an ICE and the power generated fromthe ICE powers the remedial process.

FIG. 2B is a process diagram of a remedial system for treating and/orcapturing volatile organic compounds from a vacuum tank truck using aconcentrator that utilizes an indirect chiller with two units inparallel. VOCs are introduced to the control/mixing system to beprocessed for combustion. Vapors are destroyed in an ICE and the powergenerated from the ICE powers the remedial process.

FIG. 2C is a process diagram of a remedial system for treating volatileorganic compounds from an above ground storage tank using a concentratorthat utilizes an indirect chiller with dual units in series. In thisembodiment, a compressor also feeds atmospheric air into anoxygen-nitrogen separator whereas nitrogen is used to inert a storagetank and the stripped oxygen is introduced to the control/mixing systemto be processed with the VOCs for combustion. Vapors are destroyed in anICE and the power generated from the ICE powers the remedial process.

FIG. 2D is a process diagram of a remedial system for treating volatileorganic compounds according to another embodiment of the presentinvention. In this embodiment, the designated volatile source is anactive gasoline service station with VOCs recovered from both thedispenser(s) and an underground storage tank. The concentrator in thisembodiment uses a single indirect chiller. VOCs are introduced to thecontrol/mixing system to be processed for combustion. Vapors aredestroyed in an ICE and the power generated from the ICE powers theremedial process.

FIG. 2E is a process diagram of a remedial system for treating and/orcapturing volatile organic compounds from an oil and/or natural gas wellor production field using a concentrator that utilizes amembrane/pressure swing absorption separation device. VOCs areintroduced to the control/mixing system to be processed for combustion.Vapors are destroyed in an ICE and the power generated from the ICEpowers the remedial process.

FIG. 2F is a process diagram of a remedial system for treating and/orcapturing volatile organic compounds from a gasoline service stationwith VOCs recovered from both the dispenser(s) and an undergroundstorage tank using a concentrator that utilizes a scrubber device. VOCsare introduced to the control/mixing system to be processed forcombustion. Vapors are destroyed in an ICE and the power generated fromthe ICE powers the remedial process.

FIG. 2G is a process diagram of a remedial system for treating and/orcapturing volatile organic compounds from a vacuum tank truck using aconcentrator that utilizes an adsorption device. VOCs are introduced tothe control/mixing system to be processed for combustion. Vapors aredestroyed in an ICE and the power generated from the ICE powers theremedial process.

FIG. 2H is a process diagram of a remedial system for treating and/orcapturing volatile organic compounds from an above ground storage tankusing a concentrator that utilizes a cryogenic device. VOCs areintroduced to the control/mixing system to be processed for combustion.Vapors are destroyed in an ICE and the power generated from the ICEpowers the remedial process.

FIG. 3 is a block diagram of a control/mixing system according to anembodiment of the present invention.

FIG. 4 is a logic control diagram of an air fuel controller according toan embodiment of the present invention.

FIG. 5 is a logic control diagram illustrating control logic of aprocess gas valve according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, only certain exemplaryembodiments of the present invention are shown and described, by way ofillustration. Like numbers are used to designate like components orfeatures. An index of the drawing numbers and related components orfeatures is attached as Appendix A. As those skilled in the art wouldrecognize, the invention may be embodied in many different forms andshould not be construed as being limited to the embodiments set forthherein.

In accordance with some embodiments of the invention, the remedialsystem includes one or more type of concentrators, mixing control systemand an ICE. The concentrator is used to abate some of the process gascollected from a VOC laden source, and to provide reduced energy contentof an organic volatile source so that it can be consumed by the ICEwithout restricting flow. By use of the specially constructedcontrol/mixing system, the ICE uses the VOCs in the process gas as afuel to generate energy, which can be harvested and converted to otheruseable forms of energy. When more than the minimal alternate fuel isnecessary to run the ICE, a portion of volatile source is routed directto the mixing/control system to reduce alternate fuel usage.

In certain embodiments, the VOC laden source can produce extremevariable flows and/or fuel energy values. In one embodiment, the VOCladen source is a storage tank capable of producing a process gas streamwith a fuel value or energy density between 10 BTU/ft³ upwards to 3000BTU/ft³ in a period of minutes, if not seconds. Such process gas streamswith high energy content fluctuations can only be oxidized by havinglarge or multiple flares, multiple ICEs, or multiple combinations ofother type oxidizers since a typical flare, or ICE or direct firedoxidizer only has an energy consumption capacity of approximately 105BTU/ft3 steady state. Indirect fired thermal oxidizers have an energyconsumption capacity range between 15 BTU/ft3 and 30 BTU/ft3, in steadystate condition. Alternatively, with the present invention, a variableand unsteady process gas stream with changing BTU content is managedwith a specialized control/mixing system, which will be furtherdiscussed below, combined with a VOC pretreatment method which passesthe highly variable process gas stream through a concentrator to reducethe energy mass per cubic foot to a more suitable and usable condition.

Accordingly, in certain embodiments of the present invention, theremedial system includes a concentrator adapted to reduce the organicvolatiles of a process gas stream so that a reduced consistent energycontent, and/or constant amount of fuel can be supplied to the ICE.According to yet another embodiment, the remedial system further employsa control/mixing system with a variable air fuel controller, multipleprocess control valves and a mixing chamber to regulate extremefluctuations in energy density and/or flow of the process gas stream sothat a constant air/fuel mixture is fed to the ICE.

Suitable process equipment that can be used as a concentrator includecondensers, cryogenic devices, scrubbers, carbon or other suitableadsorption/absorption material devices, and pressure swingabsorption/membrane separation devices. The following description of thepresent invention will be made with a remedial system utilizing acondenser/chiller. However, it is to be understood that other equipmentsuch as the ones mentioned above and other concentrating or separationmethods can also be used to reduce volatiles from a VOC laden source,and such embodiments when used with the ICE are within the scope of thepresent invention.

According to one exemplary embodiment of the present invention, the VOCremedial system includes an input manifold for collecting VOCs from adesignated volatile source, a condenser for condensing some of thevolatiles into a liquid stream for recovery and a control/mixing systemfor receiving the remaining vapor stream and mixing it with air and analternate fuel (i.e. propane) to form a fuel mixture feed for an ICE.The fuel mixture feed is kept at or near a stoichiometric air to fuelratio using an automated air fuel controller that blends fuels andoxygen from multiple sources based on multiple control feedback loops.In the remedial system of the exemplary embodiment, the ICE is also usedfor generating electricity and/or hydraulic energy or other types ofmechanical energy as needed. The generated energy can be used to powerthe condenser, compressors needed by the remedial system, or for otherprocess needs.

In an exemplary embodiment, the ICE initially operates on an alternatefuel source, such as propane, to drive the ICE. As adequate VOCs andSVOCs contained in a VOC laden source are conditioned and mixed with airand alternate fuel to fuel the ICE, the alternate fuel and air sourceare cut back practically to nil, other than small amounts of air andfuel that are purposely dithered in to maintain a proper air and fuelmixture at or near a stoichiometric air to fuel ratio. The air fuelcontroller of the control/mixing system blends fuel from the laden VOCsource and the alternate fuel source with atmospheric air based onoxygen content, revolutions per minute (RPM), valve biasing, alternatefuel demand/process gas bypass flow, temperature, and pressure controlfeedback loops.

The power produced by the ICE is then converted into electricity by apower generator or into hydraulic pressure by a hydraulic module. Theproduced electricity or pressure is then used to drive a condenserand/or a compressor located upstream of the ICE to start a continuousloop of generating a liquid organic condensate for reclamation, feedingresidual VOCs to the ICE for oxidation, and optionally, in certainembodiments, compressing the VOCs back to a recovery process line. Therecovered VOCs can be reused in the industrial process, rerouted backfor oxidizing in the ICE, or disposed of by other methods.

According to an exemplary embodiment of the present invention, about 80to 90% of the VOCs obtained from the laden VOC source are compressed andflow back to the process pipeline for distribution or sale. In furtherembodiments, the 10 to 20% balance of the VOCs is used as a primaryenergy source for the ICE hence eliminating the need of the alternatefuel source. The VOC percentages recovered vary dependent upon thedensity of VOCs in the actual process gas flow from the VOC ladensource.

According to another exemplary embodiment of the present invention,about 99.9% of the VOCs obtained from the laden VOC source are removedby means of condensing and oxidizing the volatiles using a condenser andan ICE that run in series or parallel and/or combination thereof.

Secondary pollutants such as carbon monoxide (CO) and nitric oxide (NOx)are byproducts of incomplete combustion of all oxidizers. For thepresent invention, these secondary pollutants are controlled by use ofan automotive catalytic converter. For the automotive catalyticconverter to function properly, the air fuel ratio must be controlledusing a specialized control/mixing system with its automated air fuelcontroller. The present invention is able to control the air fuelmixture to a point that is within the extremely small lambda window ofthe engine exhaust oxygen sensor, even with the constantly changing airfuel ratio caused by multiple fuel and air inputs from the varyingprocess vapor stream.

In yet another exemplary embodiment of the present invention, even ahigher percentage of VOCs obtained from the laden VOC source are removedby means of concentrating, condensing, compressing and oxidizing thevolatiles. In the exemplary embodiment, a high amount of VOCs is removedor recycled resulting in a reduction in the emission of toxic airpollutants as well as greenhouse gases, particularly carbon dioxide andmethane, due to a reduction of overall combustion required.

In another exemplary embodiment of the present invention, an alternatefuel source such as propane is used initially to provide fuel to the ICEand warm it up to a steady state condition. Once the ICE has reachedsteady state, the alternate fuel source is reduced as an increasedvolume of VOCs obtained from the volatile laden source are introduced.This process gas stream of VOCs is typically sufficient to power theICE. Accordingly, the remedial system of the exemplary embodimentproduces less greenhouse gas emissions as compared to other oxidizingtechnologies due to the fact that the BTU value of the vapor stream ispurposely used in lieu of the alternate fuel source to run the ICEoxidizer. Other oxidizing vehicles require a constant alternate fuelsource resulting in more energy consumed (hence more greenhouse gasemissions) to oxidize and destroy the energy found in the vapor stream.

With reference now to FIG. 2A, a process diagram of an exemplaryembodiment of the present invention is shown. The intake vacuum 765 ofICE 500 is used to extract a fuel supply managed by control mixingsystem 900 and air fuel controller 905, which will be described indetail further below, to produce power. In an exemplary embodiment, thepower generated from ICE 500 is used to drive a generator 800 and/or ahydraulic pump 810 to convert the power into electric and/or hydraulicenergy, respectively, or to run a mechanical device 805 directly off theICE 500.

In one exemplary embodiment, the produced energy is used to power acondenser unit 300 and optionally, a vacuum pump 400. The ICE 500 intakevacuum 765 and/or the optional vacuum pump 400 draws a stream of VOCsand SVOCs contained in condenser unit 300 and direct it to controlmixing system 900 to be mixed as a fuel. As the ICE 500 intake vacuum765 and/or the optional vacuum pump 400 operate, volatile components areaspirated from a designated volatile source 100. When the optionalvacuum pump 400 is present, the vacuum pump supplements the vacuum 765of the ICE 500.

The condenser unit 300 condenses a controlled portion of the VOCs andturns them to a liquid condensate. The liquid condensate is drained orpumped out of condenser unit 300 to holding tank 200 and the remainingvolatiles are fed to control mixing system 900 using the intake vacuum765 of ICE 500 and/or the optional vacuum pump 400. A recirculation line410 containing a process control valve 412 is shown. If the vacuum pump400 delivers more VOCs or flow than the ICE 500 is able to process, theexcess VOCs or flow are directed back into condenser unit 300 viarecirculation line 410. In the event the ICE 500 begins to use more thanthe minimal alternate fuel 750 necessary for control, a portion ofvolatile source 100 is routed past condenser 300 via bypass control line411 and bypass valve 413 direct to the mixing/control system 900 toreduce alternate fuel usage.

In one exemplary embodiment, a process compressor 600 is provided. Theprocess compressor 600 is capable of compressing the low pressureorganic volatiles so that the volatiles can be re-injected into a highpressure gas stream. In this way, the volatiles can reenter the processline for industrial use or be stored in a storage tank for laterdistribution or sale. In one embodiment, process compressor 600 receivesthe VOCs stream from the designated volatile source 100. In anotherembodiment, compressor 600 receives atmospheric air and deliverscompressed air to an oxygen-nitrogen separator 650, where nitrogengenerated is used to inert the process and stripped oxygen is used tomaintain combustion in ICE 500.

In the exemplary embodiment shown, the designated volatile source 100may be VOCs from a production well, glycol bath vapors or flares thatare “turned off” by use of the invention. The designated volatile sourcecan also be other sources; such as a vacuum tank truck, a gas stationunderground storage tank/dispenser, a wastewater treatment tank, aboveground storage tanks, railcars, barges, VOCs from contaminated soilremediation (SVE soil vapor extraction) and any other source ofcontrolled or uncontrolled VOCs, all of which are applicable sources forenergy to operate the invention.

In the exemplary embodiment shown in FIG. 2B, a vacuum tank truck storesthe organic fluid extracted from a pollution source such as a well, anindustrial storage tank, or a contaminated soil area. As the tank truckis filled up with the organic fluid, volatile components such as VOCsand SVOCs are displaced. The VOCs from vapor source 100 are thenevacuated by the ICE 500 intake vacuum 765 or optionally enhanced by thevacuum pump 400. The vacuum source is used to pull liquids into thevacuum tank which causes the displacement of tank VOCs through acondenser input line 305 to concentrator 301. In the exemplaryembodiment, a check valve 110 is provided in the vapor source line 100so that the VOCs will not flow back to the source. Concentrator 301includes two indirect chillers 315 run in parallel. Each chiller 315uses a heat exchanger surrounded by a coolant to condense VOCs togreater density in the process gas stream. The coolant is chilled andcirculated through each chiller by means of refrigeration unit 350,coolant holding tank 355 and pumps 250. Control of the process gas andrefrigerant flows is managed by control mixing system 900 which utilizesdifferential pressure switches 375 to monitor the pressure of theprocess gas on either side of chillers 315. The pressure feedback loopof control mixing system 900 allows the system to open and close processflow valves 414 and coolant flow valves 415 so as to maintain a constantflow of VOCs to the ICE 500. As the process gas stream leavesconcentrator 301, it first passes through liquid vapor separator 180,which removes/drops out VOC condensates which are passed on in toholding tank 200 for collection and return to the vacuum tank truck. Inthis embodiment, a pressure relief valve 420 is also provided withinconcentrator 301 for an emergency safety relief to atmosphere in theunlikely event of a simultaneous failure in the shut position of allprocess gas valves in the concentrator. Another pressure relieve valve421, set at a lower pressure setting than pressure relief valve 420,vents back into the process line so that a small pressure build up willnot cause a release to atmosphere but will allow control system 900ample time to adjust recirculation valve 412 to compensate for thechanging conditions.

In one exemplary embodiment, as shown in FIG. 2A, concentrator 301 usesa direct chiller; condenser unit 300. Condenser unit 300 is amulti-staged condenser having multiple sets of cooling coils 310. TheVOCs from a vapor source 100 are drawn to cooling coils 310 by the ICE500 intake vacuum 765 and/or enhanced by the optional vacuum pump 400 topartially condense the VOCs into a liquid condensate. The vapor streammay be circulated within condenser 300 at a high flow rate using a fan320 to increase the number of passes over the cooling coils 310 to aidin the condensing process. In one embodiment, fan 320 increases the flowrate of the vapor stream inside condenser unit 300 by ten times. Theliquid condensate exits condenser unit 300 through a condensate line 392to holding tank 200. The VOCs continuously get recycled throughcondenser unit 300 by fan 320 and go through cooling coils 310 untilmore condensate is obtained. The remaining uncondensed VOCs are thentransferred on via condenser output line 394 and pump 400 to beeventually consumed as energy/fuel by ICE 500.

In an exemplary embodiment, condenser unit 300 has multiple sets ofcooling coils 310. Each set of cooling coils 310 contains a refrigerantto provide cooling. The cool refrigerant gas is compressed by acompressor 350, causing it to become a hot and high pressure refrigerantgas. The hot refrigerant gas runs through a set of coils so it candissipate its heat and condense back into a refrigerant liquid. Therefrigerant liquid then runs through an expansion valve causing it tobecome a cold gas which goes through a set of cooling coils 310. Thecold gas contained in cooling coils 310 absorbs heat from the VOCs andcondenses the volatiles into a liquid state.

The condenser unit 300 of the exemplary embodiment of FIG. 2A includesboth a gas refrigerant system that has a plurality of cooling coils 310,as previously described, and a radiator system 370. The radiator system370 is provided to cool down ICE 500. At the same time, it is used toheat up the VOCs in condenser unit 300 if necessary. Radiator system 370includes coolant that is stored in a heat exchanger 330, a cooling coil340, a coolant input line 331, a coolant output line 332 and a coolingfan 325.

In one exemplary embodiment, coolant from the radiator system runs vialine 331 to ICE 500 to cool down the engine. The heated coolant thenexits the ICE 500 via output line 332 and is routed back to heatexchanger 330, which is used to heat the volatiles so that they may becondensed again. In the exemplary embodiment, heat exchanger 330 islocated inside condenser unit 300 so that the coolant in heat exchanger330 can be cooled down by the volatiles in condenser unit 300. The VOCsare circulated through the condenser using fan 320. As the coolantradiates heat through the heat exchanger 330 the temperature of thevolatiles increases. As the cooled coolant exits heat exchanger 330 viainput line 331 it is routed, if needed, to a cooling coil 340 forfurther cooling. The cooled coolant flows to a temperature control valve345 that either redirects the coolant back to cooling coil 340 forfurther cooling or to ICE 500 to cool down the engine if the temperatureof the coolant is low enough. It is anticipated that the coolant mayalso be used for a defrost cycle in this and other types ofcondensers/chillers that might be used.

In one exemplary embodiment, cooling coil 340 has a sufficiently largesurface area so that the coolant contained inside can be air cooled. Inanother embodiment, a fan 325 may be used to further cool the coolantbefore it enters the ICE 500.

Initially, when remedial system 10 operates, the ICE 500 is relativelycool and hence most of the coolant that exits the heat exchanger 330 viainput line 331 goes directly to the ICE 500 bypassing the cooling coil340. However, as operation of remedial system 10 continues, the ICE 500heats up thereby increasing the temperature of the coolant in the outputline 332. The heated coolant is then routed to heat exchanger 330 andcooling coil 340 before returning back to the ICE 500. Some of thecoolant may have to go through a bypass line 344 to the cooling coil 340a plurality of times if the temperature of the coolant after exitingheat exchanger 330 is not sufficiently cool enough.

Similar to cooling coil 340, heat exchanger 330 is a coiled pipe type ofexchanger that has a large surface area. In this way, more heatedsurface area is exposed to the VOCs in the condenser unit 300, therebyheating them and preventing moisture in the volatiles from being frozen.Further, in such a configuration, collection of the VOCs and SVOCscondensate is easier.

The VOCs condensate is collected at the bottom of condenser unit 300 andis eventually discharged through condensate line 392. The remaining VOCsexit through condenser output line 394 and travel to an optional vacuumpump 400 as dehumidified process gas. The ICE 500 and/or the optionalvacuum pump 400 draws a stream of process gas from the condenser outputline 394 and feeds it to a control mixing system 900. In one embodiment,the optional vacuum pump 400 is provided to enhance the process byputting the volatile source 100 under vacuum quicker rather than relyingon the vacuum 765 created by the ICE 500 alone. Recirculation line 410and recirculation valve 412 are provided to ensure any excess flow ofthe vapor is recirculated back to the condenser unit 300 and thusprevents flooding of the ICE 500 with excess fuel. A bypass line 411 andbypass valve 413 are also provided to route a portion of process gas 100around the condenser unit 300 if needed to reduce alternate fuelconsumption as controlled by the control mixing system 900.

With reference now to FIG. 2C, another exemplary embodiment of aconcentrator unit is shown. In one embodiment, the concentrator includesa glycol condenser unit 300A that has at least one glycol bath tank. Inan exemplary embodiment, the glycol condenser unit 300A has two glycolbath tanks 360 and 360A. In the present embodiment, a VOCs streamobtained from a designated volatile 100 source, an above ground storagetank for example, is extracted through a condenser input line 305 andthen routed to a first heat exchanger 380.

In an exemplary embodiment, the first heat exchanger 380 is submerged ina glycol bath 360 that has a cooled bath temperature. In one embodiment,the bath temperature ranges from about 34 to about 40° F. The first heatexchanger 380 cools and condenses moisture from the VOCs stream torender a dehumidified VOCs stream. The moisture condensate is drainedthrough a moisture condensate output line 382 to holding tank 200 andthe dehumidified VOCs stream is then fed to a second heat exchanger 390through a dehumidified vapor line 384.

The second heat exchanger 390 is submerged in the second glycol bathtank 360A that has a super cooled bath temperature. In one embodiment,the bath temperature ranges from about 14 to −25° F. The super cooledglycol bath condenses the dehumidified VOCs stream into a VOCcondensate. The VOC condensate drains through a VOC condensate line 392,which is then routed to holding tank 200 for storage. Alternatively, theVOC condensate can be routed to a process line for industrial use. Theremaining VOCs are then extracted through a condenser output line 394using the intake vacuum of the ICE 500 and/or the vacuum pump 400 androuted to a liquid vapor separator 180 where any liquid condensate isremoved and fed to holding tank 200. Downstream of liquid vaporseparator 180, VOCs are routed to control mixing system 900 via processgas line 405. The proper amounts of air, alternate fuel and VOCs arethen mixed by control mixing system 900 and fed to ICE 500 as acombustible fuel stream for oxidation and energy generation.

In one embodiment, a VOC bypass line 411 is provided. VOC bypass line411 connects the condenser input line 305 to the condenser output line394 allowing the VOCs stream to bypass a concentrator 301. VOC bypassline 411 provides VOCs to fuel the ICE 500 in the event pre-condensingis not required. In addition, bypass line 411 provides some flexibilityto control the amount of organic volatiles and/or flow rate that arerouted to the ICE 500 to compensate for fluctuations in processoperations and/or different load demands put on the ICE 500 from loadsof the electricity generator 800, and/or hydraulic pump 810 or otherequipment driven by the ICE 500. Furthermore, fuel usage feedback loop8000 (line 411 with control valve 413) as controlled by control mixingsystem 900 ensures that the ICE 500 uses BTU value from process gasfirst instead of using alternate fuel source.

In one exemplary embodiment, the first heat exchanger 380 is designed tohandle a VOCs stream having a flow rate range of about 50 to 250 SCFM,and to yield a dehumidified VOCs stream with less than 5% relativehumidity.

In this exemplary embodiment, the glycol condenser unit 300A includestwo heat exchangers 380 and 390. In other embodiments, only one heatexchanger and one glycol bath are needed to manage the VOCs stream beingprocessed. In yet another embodiment as shown in FIG. 2D, theconcentrator unit is a single or multiple (in parallel or series) shelland tube heat exchanger 300B with glycol pumped through one side of theheat exchanger 300B and the volatile stream pulled through the other.

In yet another embodiment as shown in FIG. 2F, the concentrator unitutilizes dual scrubbers 300C run in parallel. In this embodiment, VOCsin the process steam are run in parallel through line 305 to scrubbers300C where a portion of VOC gases in the process stream are scrubbedout. The remaining VOC process gas stream is then carried on to controlmixing system 900 via line 394. The addition of three way proportionalcontrol valves 386 allows one scrubber 300C to be brought off line forregeneration while allowing continued operation of the system throughuse of the second scrubber 300C. During the regeneration cycle, warmcoolant is carried to a heat exchanger in the bottom of the scrubberunit from radiator system 370 of the ICE 500, thus allowing use of theheat generated by the present invention to be used for regenerativestripping purposes.

In another exemplary embodiment, as shown in FIG. 2C, the glycolcondenser unit 300A removes about 10 to about 90 wt % of the VOCs fed toit via input line 305. In other words, the VOCs content of the outputstream in condenser output line 394 can be 10 wt % of the VOCs contentfound in condenser input line 305. Although various equipment andprocess streams of the above exemplary embodiments are described havingcertain flow rates and characteristics, it is to be understood that theequipment and process stream can possess other sizes, designs, flowrates, and flow characteristics without deviating from the spirit andscope of the present invention.

In one exemplary embodiment, glycol bath tanks 360 and 360A areinsulated and each has an input line and an output line for the glycolbath to be circulated to a refrigeration unit. In one embodiment, theglycol bath in the first glycol bath tank 360 has a first ratio of waterto glycol content and the glycol bath in the second glycol bath tank360A has the same or a different ratio of water to glycol content.

In an exemplary embodiment, both the first and second heat exchangers380 and 390 are made of stainless steel grade 316 SS. Other materialssuch as 316 SS equivalents or higher grade materials can also be used towithstand the degradation potential of the condensed VOCs. In oneembodiment, a defrost mechanism or cycle is provided to the heatexchangers 380 and 390 using the ICE 500 engine coolant circulatedthrough lines 331 and 332 to heat exchanger 334 in order to prevent theoccurrence of VOCs fogging and/or VOCs condensate freezing.

With reference now to FIG. 2E, a process diagram of an exemplaryembodiment of the present invention is shown. In the embodiment, thepower generated from ICE 500 is used to run a concentrator that useseither a membrane separation device or pressure swing absorption (PSA)device to separate inert gases from the process gas stream and thusconcentrate the VOCs in the process gas stream to the point that theysupport combustion by the ICE 500. Stripped inert gases are vented toatmosphere.

In one exemplary embodiment, heat produced by the ICE 500 is captured inradiator system 370 and circulated via lines 331 and 332 for use as heattrace on process lines on the industrial site. In this fashion, heatgenerated by the invention is captured and reused to prevent freezing oflines at industrial sites subject to below freezing temperatures. Incertain instances natural gas and oil production well sites employglycol heat trace systems used for the purpose of preventing lines fromfreezing. It is accomplished by glycol heated by a burner powered bynatural gas or electricity. With this embodiment of the invention, theradiator system 370 glycol is combined with the glycol heat trace systemon site so that electricity or gas usage is reduced or eliminated byusing the BTU value of the waste stream of the combustor. In reverse, ifthe combustor is shut down for whatever reason, the coolant from thesite heat trace system is used to keep the combustor, in the case of theICE, its engine block, at safe operating conditions.

Similarly, in another exemplary embodiment, engine exhaust heat ofembodiments of the present invention is captured for reuse on site (seeFIG. 2E). In this embodiment, engine exhaust heat is run through exhaustheat exchanger 815 located downstream of catalytic converter 550.Exhaust heat is captured and circulated through exhaust heat line 820 tovarious processes on site for use in heating or defrosting applications.Temperature sensor 2006, as monitored by the control mixing system 900,controls circulation of exhaust heat in line 820. In the embodimentshown in FIG. 2E, exhaust heat in line 820 is used for evaporative useon process or produced waste water from oil/natural gas productionfields.

With reference now to FIG. 2G, a process diagram of an exemplaryembodiment of the present invention is shown. In the embodiment, powergenerated by ICE 500 operates a concentrator that uses adsorption mediato concentrate VOCs in the process gas stream, and when the VOCs aredesorbed, the VOCs are used as combustible fuel by the ICE 500.

In one exemplary embodiment, a pair of adsorption media units 303 arefed VOCs in a process gas stream from a vacuum tank truck. VOCs are fedto the concentrator 301 via process gas line 305. Adsorption media units303 are run in parallel so as to allow continued operation of the systemduring regeneration of one of the media units 303. Three wayproportional valves 386, controlled by control mixing system 900, areused to control and isolate one adsorption media unit 303 forregeneration purposes while allowing flow of process gas through theother media unit 303. Process gas with concentrated VOC content is feddownstream from adsorption media units 303 through line 394 to controlmixing system 900 for mixing with air/oxygen and alternate fuel tocreate a combustible fuel mixture for the ICE 500.

In an exemplary embodiment, engine exhaust heat of the system iscaptured for use in regeneration of the adsorption media found inadsorption media unit 303. In this embodiment, engine exhaust heat isrun through exhaust heat exchanger 815 located downstream of catalyticconverter 550. Exhaust heat is captured and circulated through exhaustheat line 820 to adsorption media unit 303 in order to regenerate theprocessing capacity of the media. Temperature sensor 2006 and processcontrol valves 386 are used to monitor and control circulation ofexhaust heat in line 820 as controlled by control mixing system 900.

With reference now to FIG. 2H, a process diagram of an exemplaryembodiment of the present invention is shown. In the embodiment, thepower generated from ICE 500 is used to run a concentrator that usescryogenic device 304 to concentrate the VOCs in the process gas streamto the point that they are condensed back into liquid state.

In the embodiment, refrigerant unit 350, capable of cryogenictemperatures, is used to concentrate VOCs in greater concentration inthe process gas stream fed to cryogenic device 304 via line 305. VOCscondensate that is produced is drained from cryogenic device 304 and fedvia line 392 to holding tank 200 for reuse on site. The remaining VOCcontent process gas stream, if any, is discharged from cryogenic device304 and carried via line 394 to control mixing system 900 where it isfurther processed in to a combustible fuel mixture for use by ICE 500.In the embodiment, pressure relief valves 420 and 421 are provided forover pressurization protection of the system.

In one exemplary embodiment, heat produced by the ICE 500 is captured inradiator system 370 and circulated via lines 331 and 332 for use in adefrost cycle for cryogenic device 304. A differential pressure switchand coolant flow valve 415, controlled by control mixing system 900, areused in the defrost cycle of cryogenic device 304.

Referring back to FIG. 2A. At different stages of the remedial operationthere may not be enough VOCs and SVOCs in the process gas streamavailable to fuel the ICE 500, hence an alternate fuel 750 is provided.At startup of the ICE 500, a proportional amount of oxygen fromatmospheric air and alternate fuel are mixed by control mixing system900 to form an adequate, combustible fuel mixture for delivery to theICE 500. As the remedial operation continues, VOCs are withdrawn fromprocess stream 405 and blended in to the air/fuel supply by controlmixing system 900, and accordingly the amount of alternate fuel suppliedmay be suitably decreased. When the remedial operation reaches a steadystate condition and thereafter, the amount of alternate fuel can bedecreased even further. Hence at a steady state, the process gas streamcan be 99% of the fuel source used to fuel and power the ICE 500.

The alternate fuel can be natural gas, well head gas, propane, refinerygas, or any other suitable fuel that can be used as a fuel supply in aconventional manner. However, in accordance with an embodiment of thepresent invention, the alternate fuel is propane provided by a portablepropane tank 750. The oxygen source can be ambient air. In one exemplaryembodiment, air is supplied from an air atmospheric source 730 and isfiltered through an air filter 720. In another exemplary embodiment, theoxygen source is stripped oxygen that is a byproduct of a nitrogenproducing process by an oxygen-nitrogen separator 650, which will befurther discussed below. Similar to previous embodiments, theoxygen-nitrogen separator 650 may also be powered by the electricitygenerator 800 or hydraulic pump 810 of the remedial system 10.

The ICE 500 is an engine in which the combustion of fuel mixture occursin an enclosed space. The combustion of the fuel mixture is anexothermic reaction, which creates gases at high temperature andpressure. The expanding hot gases cause movement of solid parts of theengine such as pistons or rotors to create mechanical energy. Themechanical energy can be harvested and converted into electrical energyby a generator 800 and/or into hydraulic energy using a hydraulic pump810. Alternatively, the mechanical energy can be converted to otherforms of energy by other mechanical devices 805 such as a direct driveair compressor 600, for example.

In one embodiment, the provided energy is used to power the condenserunit 300. In another embodiment, the generated energy is used to poweran air compressor 600 and an oxygen-nitrogen separator 650. The nitrogenproduced by an oxygen-nitrogen seperator 650 is used to provide an inertgas blanket on a storage vessel being degassed, on a vacuum tank truck,or on a condenser input line 305, for example. The stripped oxygenproduced from the nitrogen producing process is re-introduced downstream of the process to the control mixing system 900. In yet anotherembodiment, the generated energy is used to power the process compressor600, which will be described further below.

In one exemplary embodiment, a flame arrestor 710 is provided upstreamof the ICE 500 to prevent sparks or flames that may be created from acombustion reaction in the ICE. The flame arrestor 710 absorbs heat froma flashback generated from the ICE and quenches it to a temperaturebelow what is needed for ignition. Hence, the flame arrestor 710 stopsthe propagation of a deflagration from the ICE 500 from propagating fromcontrol mixing system 900 to the fuel sources. In another embodiment, asecond and third flame arrestors 710 are provided in line 305 and line410 to provide additional protection to the designated volatile source100.

In one exemplary embodiment, a catalytic converter 550 is provided toreduce toxicity of emissions from the ICE 500. In one embodiment, thecatalytic converter 550 oxidizes carbon monoxide to carbon dioxide andconverts unreacted hydrocarbons to carbon dioxide and water. In anotherembodiment, the catalytic converter 550 further reduces nitrogen oxidesto nitrogen and oxygen.

In one exemplary embodiment, a recirculation line 410 (FIG. 2A) isprovided. Recirculation line 410 directs a partial process gas streamfrom the discharge of optional vacuum pump 400 back to the condenserinput line 305 or to volatile source 100. At the initial stage of theremedial operation, vacuum pump 400 draws and discharges a high processgas flow rate. Hence, if the process gas flow rate in process gas inputline 405 surpasses the fuel consumption requirement of the ICE 500 andthere is an excess of process gas, the excess process gas is thendirected back to condenser unit 300. Also in this way, the condenserunit 300 can effectively strip more VOCs from the process gas stream andcondense them to condensate as well. In addition, the recirculation line410 provides some flexibility to control the flow and/or the amount ofVOCs that are fed to the ICE 500 to compensate for fluctuations inprocess operations and/or different demands for electricity or hydraulicpower produced by the electric generator 800 or hydraulic pump 810,respectively.

As the remedial operation continues and especially when the system isunder vacuum, the vacuum pump 400 may discharge a lower process gas flowrate. At that point, a process control valve 412 in recirculation line410 closes as controlled by the mixing control system 900 so that all ofthe discharge from the vacuum pump 400 can be directed to the ICE 500 tomeet its fuel consumption need.

In the vacuum tank truck application depicted in FIG. 2B, it should beunderstood that the condenser, vacuum pump, control mixing system,alternate fuel source, ICE and related equipment may be mounted on thetruck for mobile use by the tank truck as needed. In such anarrangement, the system would have to be self contained, but it couldthen be used for ongoing needs of the truck while it is in transit orbeing used in other applications that do not require organic volatilesabatement.

In another exemplary embodiment (FIG. 2A), a process compressor 600 isprovided to produce high pressure gas that can be routed back to aprocess line for industrial use or storage. The VOCs from the designatedvolatile source 100 can be directed to process compressor 600. In oneexemplary embodiment, the process compressor 600 begins to operate whenthe generator 800 or hydraulic pump 810 produces adequate power. At itsfull capacity, process compressor 600 can generate a stream ofpressurized gas at a pressure greater than the line pressure of theexisting gas transport line so that the recovered pressurized gas can berouted back to the gas transport pipeline for process distribution orstorage.

Referring now to FIG. 2A, another exemplary embodiment of the presentinvention is shown. Similar to the operation of previously describedembodiments, the remedial system 10 of the exemplary embodiment draws afuel stream of VOCs from a designated source, oxidizes the fuel streamand converts the mechanical energy into other forms of energy suitableto operate the equipment of the remedial system 10 and/or otherequipment.

In this embodiment, the designated volatile source is a gas waste streamline 101 that would otherwise go to a flare or atmosphere. Gas wastestream line 101 may initially come from a highly pressurized source,such as an oil and/or natural gas well, for example. In certainembodiments, the pressure of the gas waste stream line 101 isinsufficient for introducing the waste gas stream back into a gastransport pipeline. In certain embodiments, there is a pressure decreasein gas waste stream line 101 because some of the high gas pressure wasused for ancillary work, such as running pumps. In other embodiments,the liquid product from an oil and/or natural gas well is “flashed”during a liquid phase separation process creating a low pressure gas. Inone exemplary embodiment, gas waste stream line 101 directs a portion ofthe gas flow, via condenser input line 305, to remedial system 10 of thepresent invention.

Because gas waste stream line 101 may be at high pressure, a pressurereduction valve 105 is provided to reduce the high pressure to a lowersuitable pressure. The high pressure gas stream upstream of valve 105may be used to generate work for driving on site equipment. Downstreamof valve 105, the resulting lower pressure gas stream is used as theinput stream to the remedial system of the present invention. Thereduced pressure process gas stream can be routed to an ICE 500 directlyfor fuel combustion and energy generation. In one embodiment, thereduced pressure process gas stream is directed to a concentrator unit301 via a condenser input line 305, as the process gas stream maycontain high VOCs or water vapor contents.

In an exemplary embodiment (FIG. 2C), concentrator unit 301 utilizes aglycol bath chiller(s). Similar to the operation of the glycol bathchiller as described previously, the VOCs and water vapor in the processgas stream are directed to a condenser input line 305 that goes to a setof heat exchanger(s) submerged in a glycol bath. As the vapor condenses,its condensate is collected and routed out of the heat exchangers. In anexemplary embodiment, the water condensate is collected and routed to atreatment center via a moisture condensate output line 382. In anotherexemplary embodiment, the process gas stream is further cooled tocondense the VOCs. The condensed VOCs are collected and may be routed toa storage tank 200 via a condensate output line 392.

As a gas stream of uncondensed VOCs in a condenser output line 394 isrouted out of condenser unit 300 it is directed to an ICE 500 forharvesting energy. The harvested energy can be used to power and drive aglycol bath of the condenser unit 300 and/or a process compressor 600.As can be seen in FIG. 2A, the process compressor 600 is used to providethe gas stream with sufficient pressure to rejoin an existing gas streamgoing to reclamation and sale.

Again, although the condenser unit 300 is shown, it is not needed incertain embodiments. For example, the depressurized gas stream from theflare bypass line and downstream of reduction valve 105 can be feddirectly via bypass line 411 to control mixing system 900 to operate theICE 500. The mechanical energy produced by the ICE is harvested andconverted to electrical or hydraulic energy by a generator 800 or ahydraulic pump 810. In this exemplary embodiment, the provided energy isused to power process compressor 600 so excess gas can be fed back tothe flare and/or to power other equipment as needed. Conventionalengines have been powered by well head gas where the fuel supply hasbeen “conditioned” to a spec gas standard requirement, for example, dry,constant BTU/CF content as found in sale gas. In embodiments of thepresent invention, through the use of control mixing system 900, anywaste process gas stream of any BTU content at any pressure or flow ratecan be used to operate the system. In other words, minimal sale gas isrequired to operate the system as compared to conventional engines.

Also, even though a condenser unit 300 is shown schematically in FIG. 2Aand discussed above as a method of pre-abatement, it is to be understoodthat such a schematic representation is intended to represent othertypes of concentrators as well.

With reference now to FIG. 2C, a process diagram of another exemplaryembodiment of the present invention is shown. As can be seen, thedesignated volatile source 100 in the exemplary embodiment is astorage/process tank 102. In one embodiment, storage/process tank 102contains combustible organic volatiles, such as butane, found in thehead gas portion of the tank (gas layer above the liquid level). Becauseof the butane in the head gas, nitrogen gas is fed via line 651 to tank102 to provide an inert nitrogen blanket to reduce the likelihood of anexplosion. Traditionally, a vacuum pump is employed to draw a wasteprocess gas stream from the head gas in the storage tank and feed it toan oxidizer. However, because of the low oxygen content in the storagetank head gas, a result of the introduced nitrogen blanket, process airin large volumes has to be added to make the head gas streamcombustible. In this embodiment of the present invention, anoxygen-nitrogen gas separator 650 is used to provide both the necessarynitrogen for blanketing the storage/process tank 102 and the oxygenrequired to make the head gas in the process gas stream combustible.Because what oxygen gas volume stripped off is eventually re-introduced,the air fuel ratio of the process gas stream remains balanced andcombustible by the ICE 500.

Similar to the previously described embodiments, remedial system 10 ofthe exemplary embodiments draws in a stream of head gas from a storagetank and feeds it to mixing chamber 700 as controlled by the controlmixing system 900, where appropriate oxygen, air, and alternate fuel maybe mixed to supply a combustible fuel to the ICE 500. In one embodiment,the oxygen supplied by the oxygen-nitrogen gas separator 650 is feddirectly to an input line 405 through valve 417 as controlled by thecontrol mixing system 900 before the head gas stream reaches the mixingchamber 700.

Also similar to before, the power generated by the ICE 500 is used torun some or all of the process equipment of remedial system 10. In anexemplary embodiment, the generated electric energy is used to run theoxygen-nitrogen gas separator 650. The oxygen produced byoxygen-nitrogen gas separator 650, as discussed before, is feddownstream to the process gas input line 405 to make the head gas streammore combustible. Whereas, the nitrogen produced by the oxygen-nitrogenseparator 650 is routed to storage/process tank 102 to provide anitrogen blanket over the waste water liquid.

Although a condenser may not be needed in the exemplary embodiment, itmay be needed in other embodiments. For example, in one embodiment, astream of head gas is routed to a condenser or glycol chiller to abatesome of the organic volatiles and/or to produce a dehumidified head gasstream in line 405. In the exemplary embodiment, the dehumidified headgas stream is then fed to the control mixing system 900, whereappropriate oxygen, air, and alternate fuel may be mixed to supply acombustible fuel mixture to the ICE 500.

In a similar embodiment, the ICE 500 is used to produce energy from aproduction field or volatile source that has high levels of inert gasesand low BTU content in the process gas stream. The BTU content of theprocess gas stream is concentrated in the system to increase the BTUlevels of the process gas stream to a level that will supportcombustion. Power generated by the system is used to run anoxygen-nitrogen separator. Oxygen produced is fed in to the process gasstream downstream of the concentrator, thus producing a combustible fuelstream for the ICE 500. In this way high inert content, low BTU processgas can be reclaimed to generate power to run the system and to createpower for use at an industrial site or for sale.

With reference to FIG. 2D, a process diagram of another exemplaryembodiment of the present invention is shown. Here the designatedvolatile source is a fume line that collects gasoline volatiles comingfrom various gasoline pump stations 103 that are displaced when vehiclesare being refueled. Gasoline volatiles contain cancer-causing agents andcontribute to the formation of greenhouse gases. Various statesregulations require gasoline pump stations to have special nozzles,hoses and pumps to capture gasoline volatiles that are displaced whenvehicles are being refueled. Conventionally, the captured gasolinevolatiles are rerouted to an underground storage tank, where thevolatile fumes are later evacuated and oxidized.

Similar to the previously described embodiments, remedial system 10 ofthe exemplary embodiments draws in a stream of head gas from theunderground storage tank 104 through use of the ICE 500 intake vacuumand/or optional pump 400, which is then fed to control mixing system900. Control mixing system 900 along with air fuel ratio controller 905mixes appropriate oxygen, air, head gas, and alternate fuel constituentsto produce a combustible fuel for the ICE 500. The ICE 500, in turn,generates mechanical power that may be harvested by an electricitygenerator 800 and/or hydraulic pump 810 to produce power necessary torun some or all of the process equipment of the remedial system 10.Alternatively, the electric power generated by remedial system 10 can beutilized for other industrial processes on site or put back into anenergy grid.

In an exemplary embodiment, the generated electric energy is used to runan oxygen-nitrogen gas separator 650. Although not always required, theoxygen-nitrogen gas separator 650 may be provided to produce an inertnitrogen blanket to the storage tank 104 to dampen the tank's combustionlevel. The oxygen produced by oxygen-nitrogen gas separator 650 is fedvia line 652 to a tie-in point with process gas line 405 immediatelyupstream of control mixing system 900, where the oxygen and head gas aremixed in order to make a more combustible head gas stream for the ICE500. Whereas, the nitrogen produced by oxygen-nitrogen separator 650 isrouted to tank 104 via line 651 to provide a nitrogen supply for inertblanketing of the head space of the tank.

A concentrator 301 is also provided in one exemplary embodiment. In thisembodiment, a stream of head gas is drawn from tank 104 by the intakevacuum of an ICE 500 and/or a vacuum pump 400 to a concentrator 301. Theconcentrator 301 may be a condenser or a glycol chiller that is used toabate some of the organic volatiles and/or to produce a dehumidifiedhead gas stream in line 394. The liquid condensate produced by theconcentrator 301 is routed to a condensate storage tank 200 or back tounderground storage tank 104. In the exemplary embodiment, thedehumidified head gas stream 394 is then fed to process gas line 405 andthen on to control mixing system 900, where appropriate oxygen, air, andalternate fuel may be mixed to supply a combustible fuel to the ICE 500.

With reference now to FIG. 3, a schematic of control logic of controlmixing system 900 is shown. In one exemplary embodiment, control mixingsystem 900 includes an air fuel controller 905, a mixing chamber 700,control valves 731/751/761 fueling an ICE 500. Controller 905 andcontrol mixing system 900 are designed to control the burn of processgas stream 405 in the ICE 500 in a near stoichiometric reaction thatconsumes the majority of the organic volatiles in the process gasstream. The process gas stream 405 as previously discussed may come fromdifferent designated volatile sources, hence its' exact constituents arenot exactly known but it generally includes organic volatiles. In someembodiments as shown in FIG. 2C, the process gas stream may furtherinclude inert elements such as carbon dioxide or nitrogen.

As shown in FIG. 3, the ICE 500 is connected to mixing chamber 700,controller 905 and control mixing system 900. Control mixing system 900is driven by the controller 905. Controller 905 also controls an engineignition and starter cycle 5002. In one embodiment, information fromengine RPM 1005 circuit and exhaust oxygen level 2005 circuit is fed tocontroller 905 to be processed. Based on the processed information,controller 905 adjusts engine RPM 1005 and the air to fuel ratio toarrive at a stoichiometric combustible fuel stream 760.

In one embodiment, the stoichiometric combustible fuel stream 760 isaccomplished by controlling the position of the three valves 731, 751,and 761 mixing chamber 700. Air valve 731 controls the atmospheric airinput. Fuel valve 751 controls an alternate fuel from a known sourcesuch as a propane tank 750. Process gas valve 761 controls the flow ofthe process gas 405 that comes from a designated volatile source, aspreviously discussed.

The three mixing chamber valves each use a proportionally positionedpoppet to meter the gas flow and are accurately moved by controller 905.The flow through each of the valves is determined by absolute pressureand the differential pressure across each valve. In all embodiments, theICE 500 is operated under vacuum. As a result, the engine vacuum setsthe pressure on the engine side of all three valves. In one embodiment,the air valve 731 is subjected to an atmospheric pressure on itsupstream side. In another embodiment, the upstream side of the fuelvalve 751 is slightly above atmospheric pressure. The upstream side ofprocess gas valve 761, on the other hand, can have a wide pressure rangeranging from a slightly elevated pressure to atmospheric pressure tovacuum, depending on the condition of the designated volatile source(s).

Operating parameters for running control mixing system 900 are eithermanually entered by a user via a keypad on user interface 910 (mountedon controller 905) or may be changed through a remote telemetryinterface 920 that may use an application program running on a remotecomputer. The display interface also allows the user to navigate througha menu structure for setting operating gains, limits, and set points.Typical examples of user adjustable set points are the running RPM orthe maximum opening position of process gas valve 761.

The basic system sequencing is an aspect of operation of control mixingsystem 900. Phases of operating control mixing system 900 include enginestart, warm up and stabilization, run mode; which includes opening toexternal inputs and adding engine loads, and engine shutdown.

In one embodiment, before starting the ICE 500 all three valves 731,751, and 761 are set to a closed position. Air valve 731 and fuel valve751 are then opened to a pre-set programmable initial position, whichmay depend on the environmental conditions, fuel type, and/or the typeof engine used. Process gas valve 761 remains closed during the startand warm up sequence. A number of interlocks (e.g. engine covers are allclosed, ambient LEL is at safe level) are checked to be sure it is safeto crank the engine. Controller 905 then powers the ignition system andactivates the starter motor. As the ICE 500 cranks, the fuel valve 751slowly ramps up and down from a set-point in order to arrive at an idealstarting fuel ratio and engine RPM.

A successful engine start may be detected by monitoring the engine RPMcircuit 1005 for speed above a threshold that is determined, in part, bythe maximum starter speed. When a start is detected, the starter motoris disengaged and the engine RPM control loop 1000 (FIG. 4) is activatedto run the motor at an idle speed. If the engine RPM falls to a stop,controller 905 will pause a few seconds and then restart again.

In one embodiment, the engine RPM control loop 1000 proportionally opensand closes air valve 731 and fuel valve 751 in mixing chamber 700 asnecessary to control the ICE 500 to run at the idle set point RPM. Ifcontroller 905 detects that the engine is running at a lower speed thanthe idle set point, it will increase the valve positions for both airvalve 731 and fuel valve 751. If the measured RPM is higher than the setpoint, the valves will move in the closing direction. The proportion ofair and fuel immediately after engine start is the proportion settingthat was on the two valves 731 and 751 at the time that a start wasdetected.

In one embodiment, a short time after the engine start is confirmed, thefuel ratio loop 2000 (FIG. 4) is engaged. Fuel ratio loop 2000 comparesthe engine exhaust oxygen level output signal 2005 against aprogrammable set point. In one exemplary embodiment, there is a delaybefore the fuel ratio loop 2000 is engaged because the oxygen sensor2002 will not function properly until it is hot. Oxygen sensor 2002 isused to determine if the ICE 500 is running too rich, too lean, or neara stoichiometric ratio. The comparable set point allows fine tuning ofthe ideal engine condition which may be optimized, for example, toaccommodate different fuel types and different catalytic converter 500configurations (see FIG. 2A). If the fuel ratio loop 2000 determinesthat the engine is running on the lean side, it will increase theproportion of fuel to the ICE 500 by setting fuel valve 751 (FIG. 3) toopen to a wider position. Conversely, if the ICE 500 is running toorich, the fuel ratio loop 2000 will decrease the proportion of openingof fuel valve 751 accordingly.

After the ICE 500 has successfully started and stabilized at the idlespeed for a programmable period of time, the ICE 500 begins totransition into a running speed phase. At the running speed phase, fuelrequirement is typically higher because a higher RPM requires moreengine power and more fuel flow through the control mixing system 900.Higher flow and engine power means that more of process gas 405 will beprocessed by remedial system 10.

In one embodiment, the ICE 500 operates at the running speed for aprogrammable period of time to allow engine temperature and otherrunning conditions to stabilize. This stabilization time period isimportant as it allows an accurate determination of the amount of energyrequired to run at the programmed set point, referred to as the“baseline” condition. Comparison against this baseline condition, asrecorded by the control system, may be used to estimate the energycontent of the incoming process gas stream 405.

In one embodiment, once the ICE 500 is in a steady running phase, thecombustion of the process gas stream 405 can proceed. This isaccomplished by slowly opening process gas valve 761 (FIG. 3), whichallows the ICE 500 to draw in flow from the process gas stream 405. Asthe process gas stream 405 enters the ICE 500 the conditions of RPM andfuel ratio may change. These changes can be complex, but both RPM loop1000 (FIG. 4) and fuel ratio loop 2000 adjust air valve 731 and fuelvalve 751 as necessary to keep the ICE 500 running within its correctoperating range.

Process gas stream 405 may contain different organic and non organiccomponents (VOCs) that may result in different run conditions. In oneembodiment, process gas stream 405 may contain mostly air and hence isvery lean. As a result, air valve 731 may move toward a closed positionand process gas valve 761 may move toward a more open position to allowmore process gas to flow through. In the present embodiment, fuel valve751 may maintain its position as air valve 731 and process gas valve 761simply offset where the source of air is coming from. In anotherembodiment, the process gas stream 405 may contain high organicvolatiles hence a rich fuel source. As a result, fuel valve 751, whichcontrols the source of the alternate fuel, begins to close off asprocess gas valve 761 begins to open more to allow more flow fromprocess gas stream 405. In this embodiment, air valve 731 may not changemuch because control mixing system 900 is simply exchanging where thesource of fuel is coming from. In another exemplary embodiment, theprocess gas stream 405 may be near the correct fuel ratio. In this case,both air valve 731 and fuel valve 751 may close off as process gas valve761 may open wider to allow more of the process gas stream 405 to comethrough.

In yet another exemplary embodiment, process gas stream 405 may containa high level of inert compounds resulting in low percentage oxygencontent. In this exemplary embodiment, both air valve 731 and fuel valve751 have to be in an open position to maintain an accurate air fuelratio while doing the additional work of heating the inert compounds andmoving more volume through the engine.

The key point is that regardless of the input condition, control mixingsystem 900 automatically makes adjustments to valves 731, 751, and 761through operation of the two closed feedback loops, RPM loop 1000 andfuel ratio loop 2000, in order to keep the ICE 500 running at a correctsteady state condition.

In certain embodiments, when the ICE 500 is at a steady state condition,process gas valve 761 remains in an open position. The process gas valve761 open position, however, has to be changed (increased or decreased)when an upset condition such as inadequate fuel ratio and/or flow in theprocess gas stream 405 or any other change in the process conditionsoccurs. When any change in process conditions is detected, process gasvalve 761 may either be scaled back or forward from its original openposition, or in some cases it may be driven back to a closing position.Examples of upset conditions that compel process gas valve 761 to backoff or close completely include, but are not limited to; air valve 731or fuel valve 751 approaches a fully closed position, any of the threevalves 731, 751, and 761 exceeds a high limit open position, theperformance of engine RPM 1005 is erratic, and/or the engine vacuumlevel is too low. When air valve 731 approaches a fully closed position,air fuel controller 905 can no longer regulate the engine RPM 1005.Similarly, when fuel valve 751 approaches a fully closed position,controller 905 can no longer regulate engine RPM 1005 or the fuel ratioin fuel stream 760 (FIG. 3).

In certain embodiments, a mechanical load may be connected to the ICE500. This is done either to generate the necessary power required byremedial system 10 or other process needs and/or to increase the workload and thereby increase the amount of process gas 405 coming in to thesystem. The mechanical load can be added either before or after processgas valve 761 is opened to allow process gas stream 405 to be processed.The addition of load has the effect of lowering the engine vacuum andthus requiring more work to be done. Increased work requires more fuelflow 760 to the ICE 500. As the ICE 500 is typically supplied primarilywith fuel from process gas valve 761, the net result is the processingof an additional volume of process gas 405 in a given period of time.More load means more work and results in more of process gas 405 beingremediated. Again, the presence of RPM loop 1000 and fuel ratio loop2000 makes control mixing system 900 insensitive to changes in eitherthe content of the gas process stream 405 or to the applied load andallows proper functioning of remedial system 10.

In a shutdown mode, if a load had been applied it is now removed beforeprocess gas valve 761 is shut off. Process gas valve 761 is slowlyclosed off to be in sync with the opening of air valve 731 and fuelvalve 751. The closing and opening synchronization of the three valves731, 751, and 761 is important to maintain a smooth engine operation ascontrol mixing system 900 switches the air/fuel components in enginefuel stream 760 from process gas stream 405 to the air source 730 andalternate fuel source 750. As process gas valve 761 is fully shut off,air valve 731 and fuel valve 751 begin to slowly and proportionallyclose to taper off and eventually stop fuel stream 760 that is routed tothe ICE 500. When RPM 1005 has dropped to zero and all three valves areclosed, the ignition system is then switched off. In one embodiment,each process of removing the load and switching the valves can be donein several seconds.

With reference now to FIG. 4, a control algorithm for control mixingsystem 900 includes RPM loop 1000, fuel ratio loop 2000, and the valvebiasing loop 3000. In one embodiment, as previously discussed, theengine RPM 1005 is controlled by the positions of air valve 731 and fuelvalve 751. If the positions of the valves are over the normal operatingrange, excess flow to the ICE 500 and higher engine RPM 1005 may result.To control the engine RPM 1005, it must first be measured. In oneembodiment, the RPM 1005 is measured based on the ignition coil inputwhich may pulse once per two engine revolutions per cylinder. The RPMfilter block 1001 keeps a running average of the last several pulsetimes. The length of the running buffer is set equal to the number ofcylinders so that slight variations in pulse times from cylinder tocylinder will not cause unnecessary noise in the RPM result. The RPM iscalculated as 120/the number of cylinders/the pulse time.

The difference between target RPM 1006 and measured engine RPM 1005creates an error that is multiplied by gain 1002. That result becomesthe key component in an output that is then limited to become valveerror 1003. An additional input to the valve error 1003 calculation isthe first time derivative of the engine RPM 1005 multiplied by the gainKDrpm 1004. The first time derivative of RPM is calculated by taking thedifference between the present RPM and the previously calculated RPM andit is a measure of how fast the RPM is changing. The addition of thisterm provides stabilizing damping to RPM control loop 1000.

The resulting valve error 1003 signal is proportionally scaled by anengine valve bias 3001 signal to directly create the air valve positioncommand 7310. Valve position command 7310 is limited to preventimpossible to achieve negative commands and to not allow the valve toopen beyond a reasonable control range for the engine.

Fuel valve position command 7510 is similarly processed from the samevalve error 1003 signal so that air valve 731 and fuel valve 751 willalways be proportionally commanded from the RPM loop 1000 control errorsignal. Fuel valve 761 has an additional input from the fuel errorsignal 2001, but from the perspective of the RPM error signal, thesechanges are separate.

Similarly to RPM loop 1000, fuel ratio loop 2000 controls the enginefuel ratio by adjusting process gas fuel valve position 7610 (FIG. 5) ontop of its command from RPM loop 1000. To create fuel valve command7510, the measured effectiveness of the engine burn is detected byoxygen sensor 2002 (FIG. 3). Engine exhaust oxygen sensor output 2005 iscompared to oxygen target value 2003 by taking the difference betweenthe two. That difference error is multiplied by gain KO₂ 2004 and inputinto time domain integrator 2100. The output of time domain integrator2100 is limited to become fuel error 2001. Time domain integrator 2100in this control loop serves two key purposes. The first is to filterincoming error because sensor gain is so high that direct usage wouldresult in a highly unstable control loop. The second purpose is toassure a very low steady state error in the desired (target) commandvalue in control loop 2000. The resulting fuel error 2001 is added tovalve error 1003 from the RPM loop 1000 to produce the proportional fuelvalve command 7510.

Valve biasing control loop 3000 compares valve error 1003 against atarget valve command 3003. The result is passed through gain (KGAUG)3002, integrator 3100 and limited by bias limiter 3004 to produce anengine valve bias signal 3001. Engine valve bias signal 3001proportionally adjusts air valve command 7310 and fuel valve command7510 over a very limited range that is determined by bias limiter 3004.

Although it is subtle, valve biasing loop 3000 provides a small bias tothe control valves that drives the RPM loop 1000 steady state error tozero in a way that does not significantly affect the performance of RPMloop 1000 and fuel ratio loop 2000. The significance of clearing the RPMsteady state error to zero in this way is that it effectively changesthe gain of RPM loop 1000 and fuel ratio loop 2000 as a function ofvalve position. Thus increased gain for increased valve position greatlyimproves performance of remedial system 10 over the broad range ofvariation in process gas components and engine loads.

With reference to FIG. 5, the control algorithm for operating processgas valve 761 is shown. The operation of process gas valve 761 isindependent of air valve 731 and fuel valve 751 because of the closedloop nature of operation for valves 731 and 751. While the operation ofprocess gas valve 761 may cause a response from air valve 731 and fuelvalve 751, process gas valve 761 can continue to open as long as theengine performance does not reach its operating range limits. Processgas valve 761 remains open until or unless any of air valve command7310, fuel valve command 7510, process gas valve command 7610, engineRPM control loop 1000 and/or engine vacuum pressure reaches or exceedsits correct operating range.

As can be seen in FIG. 5, as long as none of the nine “out of range”conditions are met, none of the “out of range” switches are closed, andtherefore the only input to process gas valve command integrator 7600 isthe process gas increment gain 7601. Process gas valve 761 will continueto operate in the open direction until one or more of the “out of range”decisions are true. Notice that a true decision closes a switch thatsubtracts process gas increment gain 7601, multiplied by a gain Δ, awayfrom the process gas increment gain 7601 setting that drives integrator7600. In all cases but one, the gain A is greater than one with theresult that integrator 7600 will reverse direction, thus commandingprocess gas valve 761 towards the closed direction. The logic controlconcept is that a reduction of the process gas valve command 7610 shouldtake away the “out of range” condition. The only decision with a gain Aof one is found when process gas valve command 7610 has hit its limit.Because the gain A is one, the net result of this occurrence is acanceled input to integrator 7600 which results in no change to processgas valve command 7610.

In FIG. 3, fuel usage/bypass feedback loop 8000 is shown. Fuel usagefeedback/bypass loop 8000 allows a portion of process gas to bypassconcentrator 301 and be fed directly via line 411 to control mixingsystem 900 and ICE 500. The VOC content of the process gas stream thatis being processed typically is variable in nature. If the VOC BTUcontent is greater than BTU combustion capacity of the system then allthe process gas stream is fed to the concentrator and then to the ICE;if the VOC BTU content is lower than the BTU combustion capacity, thenthe appropriate portion of the gas stream is automatically routed viabypass line 411 to control mixing system 900 via bypass control valve413. Fuel usage feedback loop 8000 accomplishes this task by monitoringalternate fuel valve 751 and controlling bypass control valve 413.Control mixing system 900 is constantly monitoring and controlling theposition of alternate fuel valve 751 during operation of the ICE 500. Ifalternate fuel valve 751 is trending towards a closed position,indicating a higher VOC content in the process gas, control mixingsystem 900 registers this and moves bypass control valve 413 to a moreclosed position. Conversely, if alternate fuel valve 751 is trendingtowards the open position, indicating a lower VOC content in the processgas stream, control mixing system 900 will move bypass control valve 413towards a more open position. As bypass control valve 413 moves from amore open to a more closed position, the amount of process gas streamgoing in to concentrator 301 is adjusted automatically, thus allowingmore or less of the VOC laden process gas stream to be concentrated. Asbypass control valve 413 moves towards a more closed position, moreprocess gas will be run through concentrator 301 and the VOC level onthe process gas stream reduced as VOCs are removed from the gas streamby the concentrator. The purpose of fuel usage feed back loop 8000 is tominimize alternate fuel use of the system.

With reference to FIG. 3, the pressure feedback loop 8500 is shown. Thepressure feedback loop, as controlled by control mixing system 900,provides process control for three important functions of the system. Afirst function of pressure feedback loop 8500 is to allow recirculationof process gas from control mixing system 900 back to the volatilesource. If control mixing system 900 registers that the incoming processgas stream has more BTU value than the ICE 500 combustion capacity, itwill close process valve 413 as previous described, and divert andcirculate the process gas stream back to the volatile source. Controlmixing system 900 monitors pressure vacuum switch 430 and when pressureis higher than a predetermined set point, control mixing system 900opens process control valve 412 and allows process gas to flow back vialine 410 to the volatile source. In this fashion, excessive VOC levels(high BTU value) in the process gas stream to control mixing system 900are re-circulated for multiple passes. In another embodiment of thiscontrol loop a portion of the required vacuum work (engine manifoldvacuum pressure 765) is transferred from the engine intake manifold topump 400 whereas pump 400 reduces pressure at the mixing chamber 700specifically to the benefit of process gas valve 761. This results in amore stable control of the process gas valve 761 in that pump 400becomes the majority vacuum source instead of the intake engine manifoldvacuum 765 resulting in a higher resolution for process gas valve 761.This also results in increased vacuum capacity for a system with twovacuum pumps 400 and 500/765 plumbed in series.

A second function of pressure feedback loop 8500 is control for variousdefrost applications of a system. In one embodiment as shown in FIG. 2B,control mixing system 900 utilizes pressure feedback loop 8500 tomonitor and control two differential pressure switches 375 associatedwith heat exchangers 315. When pressure higher than a predetermined setpoint is determined in either of heat exchangers 315, control mixingsystem 900 manages process flow valve 414 and coolant flow valve 415 soas to control process flow and coolant flow through the heat exchangers315 that requires defrosting. When pressure from pressure differentialswitch 375 drops below the predetermined set point, the process flowvalve and coolant flow valve return to normal operating position.

In another embodiment as shown in FIG. 2D, pressure feedback loop 8500is used to enable control of a defrost cycle for heat exchanger 300B. Ifcontrol mixing system 900 registers a higher pressure on differentialpressure switch 375 than a predetermined set point, it will throttledown the three way proportional control valves 386 and thus reduce theflow of refrigerant through heat exchanger 300B. With less refrigerantflow through heat exchanger 300B, it will warm up and defrost. Oncepressure has dropped below a predetermined set point, control mixingsystem 900 opens up proportional control valves 386 and allows higherrefrigerant flow through heat exchanger 300B.

In another embodiment as shown on FIG. 2H, pressure feedback loop 8500is used to monitor and control a defrost application for cryogenicdevice 304. If control mixing system 900 registers a higher pressure ondifferential pressure switch 375 than a predetermined set point, it willopen up process flow valve 414 and allow flow of warm engine coolantfrom radiator system 370 to circulate via lines 331 and 332 through aheat exchanger adjacent to the cryogenic device 304. Once pressure hasdropped below a predetermined set point, indicating a defrosted heatexchanger, control mixing system 900 closes process flow valve 414 toisolate the defrost heat exchanger from radiator system 370.

A third function is shown in FIG. 2B, pressure feedback loop 8500 isused to control an adjustable orifice valve 440 to maintain aprogrammable vacuum level on the entire process gas supply of thesystem. If control mixing system 900 registers a pressure outside theprogrammed set point based on pressure transducer 430, it will open orclose the adjustable orifice valve 440 and thus reduce or increaseprocess flow to maintain programmed vacuum.

In FIG. 3, temperature feedback loop 9000 is shown. Temperature feedbackloop 9000 is used for control of various defrost and heat demandapplications for embodiments of the present invention. In one embodimentas shown in FIG. 2A, control mixing system 900 utilizes temperaturefeedback loop 9000 to monitor and control coolant flow valve 415delivering coolant to heat exchanger 330. When temperature higher than apredetermined set point is sensed at temperature sensors 2006, controlmixing system 900 opens coolant flow valve 415 to allow flow of coolantfrom radiator system 370 and defrosting of heat exchanger 330. Whencontrol mixing system 900 senses temperature is below the predeterminedset point, control mixing system 900 then closes valve 415 to stopcoolant flow to defrosted heat exchanger 330.

In another embodiment as shown in FIG. 2C, temperature feedback loop9000 is used to enable control of a defrost cycle for heat exchanger334. If control mixing system 900 registers a higher temperature oneither of temperature sensor 2006 than a predetermined set point, itopens coolant valve 415 to allow flow of coolant from radiator system370 and defrosting of heat exchanger 334. When control mixing system 900senses temperature is below the predetermined set point, control mixingsystem 900 then closes valve 415 to stop coolant flow to defrosted heatexchanger 334.

As shown in various figures (FIGS. 2A, 2B, 2C, 2D, 2H) control mixingsystem 900 also uses temperature feedback loop 9000 to monitor andcontrol operation of refrigeration unit 350. When temperature dropsbelow a predetermined set point, as read by sensors 2006, control mixingsystem 900 turns on refrigeration unit 350 to start coolant flow throughan associated heat exchanger. When the temperature drops below apredetermined set point, control mixing system 900 then turns offrefrigeration unit 350.

In another embodiment as shown in FIG. 2E, temperature feedback loop9000 is used to enable control of two different applications requiringheat. The first application utilizes heat from radiator system 370 toprovide heated glycol coolant for heat tracing of process linesassociated with a glycol heat trace system at a productionwell/production field. If control mixing system 900 registers a demandfor heat based on a predetermined set point, it opens coolant valve 415to allow flow of coolant from radiator system 370 and coolant flowthrough the heat traced lines.

The second application requiring heat in FIG. 2E is one where heat isrequired for evaporative uses in water pollution remediation. If controlmixing system 900 registers a higher temperature on temperature sensor2006 than a predetermined set point, it opens exhaust heat exchangervalve 416 to allow flow of heated atmospheric air from exhaust heatexchanger 815 and flow via line 820 to the remediation process. Whencontrol mixing system 900 senses temperature is below the predeterminedset point, control mixing system 900 then closes valve 416 to controlflow to the remediation process. In other embodiments for waterpollution remediation, it should be understood that heat source fromradiator system 370 or other heat sources from embodiments of theinvention may be used for such remedial processes.

In FIG. 3, the oxygen content feedback loop 9500 is shown. Oxygencontent feedback loop 9500 allows control mixing system 900 to monitorand provide oxygen to the process gas stream 405 and ICE 500. The VOCand inert gas content of the process gas stream that is being processedtypically is variable in nature. If the process gas stream has too highan inert gas content (lack of oxygen), the addition of oxygen isrequired to support combustion by the system. Control mixing system 900monitors three different parameters in order to determine the oxygenrequirement of the process gas stream being processed by embodiments ofthe current invention. The position of air valve 731, the ICE 500exhaust gas temperature 2006 and ICE 500 engine manifold vacuum pressure765 are simultaneously monitored and compared to baseline parameters todetermine the oxygen requirement of the incoming process gas stream 405.If additional oxygen is required for proper combustion, control mixingsystem 900 opens oxygen content control valve 417 and allows oxygengenerated by oxygen-nitrogen separator 650 to flow to process gas line405 and control mixing system 900 where the oxygen is combined withatmospheric air, alternate fuel and process gas to produce a combustiblegas mixture for ICE 500. Another embodiment of the control loop would beto use a direct measurement of oxygen level with an inline O2 sensor inprocess gas line 405, also monitored by control mixing system 900 toprovide a comparison value of the oxygen content in lieu of or inconjunction with the three baseline parameters of air valve 761position, exhaust gas temperature and engine manifold vacuum pressure.

Example 1

Remedial system 10 can be used in any number of various applicationswhere there is a source of organic volatiles, VOCs. For example, it hasbeen found that process gas that is routed to a flare for oxidation caninstead be treated with remedial system 10 of the present invention andelectricity generated as a byproduct of the inventions' oxidationprocess. In one exemplary embodiment, about 20% of a 60 SCFM process gasstream going to a flare for oxidation is diverted to the remedialsystem. The diverted process gas stream is hooked up directly to an ICE500. Control mixing system 900 and air fuel controller 905 on the ICE500 creates a mix of about 99% of the process gas and 1% of propanealternate fuel to form a mixed fuel for combustion by the ICE 500. Inthe exemplary embodiment, the ICE 500 then is used to run a generatorwhich produces between 25 to 40 kW of usable electricity for the site.In another embodiment, no gas will be directed to flare in favor of theinvention operating a gas pumping station and putting waste gas backinto the pipeline for sale.

Example 2

In another exemplary embodiment, a process gas stream is directed to thecondenser unit of the present invention. The condenser unit removesabout 10 to 20% of the VOCs and SVOCs in the process gas stream at theinitial stage of operation of the remedial system. At the steady statecondition of remedial system 10, the condenser removes about 20% to 90%of the VOCs (depending on VOC type) in the process gas stream before itreaches the ICE 500. The net result, following oxidation by the ICE 500,is over 99.9% removal of VOCs in the process gas stream. In thisexemplary embodiment, the ICE 500 is a single engine rated at less than50 brake horsepower (BHP). Although an ICE with a larger engine ormultiple engines can be used, it may not be necessary since thecondenser unit removes most of the volatile contents from the processgas stream.

In view of the foregoing, an embodiment of the present inventionprovides a remedial system that has a concentrator adapted to remove aportion of a fuel supply obtained from a VOC laden source and an ICE forconverting the remaining fuel supply to a useable form of energy. Inanother embodiment, the remedial system includes a control mixing systemadapted to regulate extreme fluctuations in energy density and/or flowof the process gas stream and provide a constant feed and/or a constantfuel concentration to the ICE. In a further embodiment, the remedialsystem includes both a concentrator and a control mixing system adaptedto regulate the flow of fuel to an ICE. In certain embodiments, theconcentrator is a condenser that removes moisture and/or condensesorganic volatiles from a VOC laden source.

In the above exemplary embodiments, the remedial systems of variousembodiments of the present invention produce less greenhouse gasemissions and have a smaller carbon footprint than other traditionaloxidation systems while reclaiming and converting renewable energy toother forms of useable energy. Embodiments of the present invention havebeen accepted and operating permits issued for use in air pollutioncontrol districts (i.e. 11 permits issued by the South Coast Air QualityManagement District in California), New Jersey, Texas and elsewhere.Embodiments of the invention are used in place of other pollutioncontrol technologies that will not meet current EPA or local emissionregulations.

While particular process equipment and methods have been described inconnection with what is presently considered to be practical exemplaryembodiments, it is to be understood that the invention is not limited tothe disclosed embodiments, but, on the contrary, is intended to covervarious modifications and equivalent arrangements and equivalentsthereof.

What is claimed is:
 1. A remedial method for utilizing volatile organiccompounds comprising: collecting a process stream laden with volatileorganic compounds; concentrating the volatile organic compounds toproduce a liquid condensate and a vapor feed source; providing an airsupply stream; providing an alternate fuel stream; mixing the vapor feedsource, the air supply stream and the alternate fuel stream to produce amixed fuel stream; directing the mixed fuel stream to a combustor togenerate power.
 2. The method of claim 1, further comprising splittingoff from the vapor feed source a recycling feed.
 3. The method of claim2, further comprising compressing the recycling feed to produce a highpressurized gas.
 4. The method of claim 1, further comprisingcompressing at least a portion of the vapor feed source to provide apressurized vapor feed stream for reuse.
 5. The method of claim 1,further comprising compressing the vapor feed to provide a pressurizedvapor feed stream for sale.
 6. The method of claim 1, further comprisingproviding nitrogen to the process stream laden with volatile organiccompounds.
 7. The method of claim 1, further comprising providing oxygento the process stream laden with volatile organic compounds.
 8. Themethod of claim 1, further comprising using the power generated by thecombustor to drive a power generator to generate electric energy anddirecting the electric energy to an oxygen-nitrogen separator to provideoxygen and nitrogen.
 9. The method of claim 1, further comprising usingthe power generated by the combustor to drive a power generator togenerate hydraulic energy and directing the hydraulic energy to anoxygen-nitrogen separator to provide oxygen and nitrogen.
 10. The methodof claim 1, further comprising using the power generated by thecombustor to drive a direct mechanical energy generation device anddirecting the engine driven direct mechanical energy to anoxygen-nitrogen separator to provide oxygen and nitrogen.
 11. A remedialsystem for treating volatile organic compounds comprising: a wastestream line of pollutants; a mixing chamber adapted to receive the wastestream line, an air supply line, and an alternate fuel supply line,wherein the mixing chamber has a mixed fuel outlet line; a controlmixing system adapted to keep a ratio of air and fuel in the mixed fueloutlet line; an internal combustion engine adapted to receive the mixedfuel outlet line; and means for converting mechanical energy from theinternal combustion engine to another form of energy.
 12. The system ofclaim 11, wherein the means for converting mechanical energy is agenerator for generating electrical energy.
 13. The system of claim 11,wherein the means for converting mechanical energy is a hydraulic pumpfor generating hydraulic energy.
 14. A remedial system for treating fortreating volatile organic compounds comprising: a tank adapted tocontain combustible organic volatiles; a source line connected to a headspace of the tank; a mixing chamber adapted to receive the source line,an air supply line, and an alternate fuel supply line, wherein themixing chamber has a mixed fuel outlet line; a control mixing system tokeep a ratio of air and fuel in the mixed fuel outlet line; an internalcombustion engine adapted to receive the mixed fuel outlet line; anoxygen-nitrogen separator run by the internal combustion engine andhaving an oxygen output line and a nitrogen output line; wherein theoxygen output line is connected to the control mixing system and thenitrogen output line is connected to the head space of the tank.